Chronic Inflammation Tissue Repair

Question 1

what is remodeling?

Answer 1

healing by deposition of collagen

Question 2

what are the two steps of remodeling?

Answer 2

remodeling of granulation tissue with immature connective tissue
conversion of immature collagen to mature collagen

Question 3

what are the key players in tissue repair?

Answer 3

fibroblasts and collagen
endothelial cells
epithelial cells
extracellular matrix
matrix metalloproteinase (MMP’s)

Question 4

what stimulates angiogenesis?

Answer 4

hypoxia
release endothelial cell growth factors: FGF, VEGF, PDGF

Question 5

how long does epithelialization take?

Answer 5

3-5 days

Question 6

during wound repair, _____________________ must move laterally across the wound surface to fill the void

Answer 6

keratinocytes and mucosal epithelial cells

Question 7

what are the four steps in scar formation?

Answer 7

angiogenesis
formation immature granulation tissue
remodeling immature granulation tissue into mature connective tissue
wound contraction

Question 8

what is angiogenesis?

Answer 8

sprouting new vessels from existing ones

Question 9

what does vascular endothelial growth factor (VEGF) do?

Answer 9

stimulates migration and proliferation endothelial cells: initiates capillary sprouting

Question 10

what is granulation tissue composed of?

Answer 10

fibroblasts, loose connective tissue, newly formed vessels, interspersed leukocytes

Question 11

what cells specifically play a role in wound contraction?

Answer 11

myofibroblasts: contract instead of producing collagen

Question 12

what is wound contraction characteristic of?

Answer 12

large wounds
chemical injuries
burns

Question 13

what happens within 24-48 hours in a skin wound?

Answer 13

epithelial cells from both edges migrate and proliferate along dermis, depositing basement membrane components as they progress

Question 14

can foreign bodies- surgical implants/bone- impact healing?

Answer 14

yes

Question 15

what are the essential things for the proliferation stage of tissue repair?

Answer 15

retention of normal stromal elements of the extracellular matrix to provide structural framework for repair
normally functioning fibroblasts, myofibroblasts, endothelial cells, pericytes, epithelial cells
initial deposition collagen and other key extracellular matrix molecules after fibroblasts have proliferated and fortified

Question 16

what is extracellular matrix composed of (not cells)?

Answer 16

collagen
proteoglycans
glycoproteins
elastic fibers

Question 17

what causes the vasodilation and increased permeability necessary for the first step of angiogenesis?

Answer 17

vascular endothelial growth factor
nitric oxide

Question 18

what are the cytokines that participate in remodeling?

Answer 18

TGF-beta
PDGF
FGF-2
MMPs
tissue inhibitors of MMP

Question 19

what do fibroblasts produce (other than collagen and extracellular matrix)?

Answer 19

MMPs
chemokines that regulate the composition of the extracellular microenvironment (TGF-beta, PDGF, VEGF)

Question 20

what do metalloproteinases (MMPs) do?

Answer 20

degrade basement membrane and ECM components, cleave intercellular adhesion, release growth factors